This project will continue and extend analyses of an existing longitudinal data base to further identify and quantify precursors, correlates, and sequelae of drug use. Approximately 12,000 students, ranging from the 4th to the 12th grade, were tested each year for five years under conditions that maintained year-to-year linkage for individual subjects. Data were collected regarding drug use, attitudes toward drug use, knowledge about drugs, personality, cigarette smoking, attitudes toward cigarette smoking, grade point average, school attendance, suspensions, and high school graduatiion. Checks of internal consistency show that the quality of the data base is high. Analyses already completed have provided new information concerning psychosocial precursors of drug use and changes in psychosocial variables that occur after initiation or escalation of drug use.